Specifically staffs. Say you are a level 8 wizard with magical lineage:fireball (because of course).
You could craft a staff of fireballs for 9600. The same wizard could craft a staff of intensified lightning bolt for 12800. The question is, how much does a staff of intensified fireball cost?
For our wizard, an intensified fireball is a 3rd level spell, so it seems like 9600 is the correct answer, much like a paladin could craft a lesser restoration wand for 750 gp.
I could see the argument for 12800, but metamagic reductions are not well defined in the PF rules.
Nope.
Your feats, unless the specify magic item creation, do not affect magic items.
So just because you can cast the spell in a lower spell slot for yourself, it still is priced as the original spell slot.
A staff of intensified fireball would be based on:
The materials cost is subsumed in the cost of creation: 400 gp × the level of the highest-level spell × the level of the caster, plus 75% of the value of the next most costly ability (300 gp × the level of the spell × the level of the caster), plus 1/2 the value of any other abilities (200 gp × the level of the spell × the level of the caster). Staves are always fully charged (10 charges) when created.
So you would price it based on 4th level spell, and I believe the minimum caster level for a 4th level spell, which would be 7. Except weirdly caster level 11 seems to be the minimum on staves.
So it would cost 12800gp, and you would pay have that for crafting. It would be more if the staff had any other spells though. With the drawback being this staff could only be recharged by intensified fireball.
Also the Craft Staff feat requires caster level 11, so you can't even craft staves yet.
It's also worth noting that lesser restoration is a first level paladin spell, so it of course cost 1/2 750gp to make, but only if a paladin makes it.
And the game makes the assumption that clerics and wizards make all magic items, unless the spell is unavailable to those classes and then there is an order to determine which class is used. Of course, this is only for object to be bought in the game world, so if the player actually makes one then he gets it at that cost.
Otherwise players are buying a wand of lesser restoration as a 2nd level cleric spell which costs 4500 gp.